Process of distilling and cracking oils.



J. A. SWATON.

PROCESS OF DISTILLING AND CRACKING OIL& APPLICATION FILED AUG.20. 1917-.

1,260,731. Patented Mai. 26,1918.

INVENTUR BY A WATON ATTORNE Y5 JOSEPH A. SWATCH, OF LOS ANGELES, CALIFORNIA.

PROCESS OF DISTILLING AND CRACKING OILS.

Specification of Letters Patent.

Patented Mar. 26, 1918.

Application filed August 20, 1917. Serial No. 187,161.

To all whom it may concern:

Be it known that I, JOSEPH A. SWATON, a citizen of the United States, residing at Los Angeles, in the county of Los Angeles and State of California, have invented new and useful Improvements in Processes of Distilling and Cracking Oils, of which the following is a specification.

My invention relates to a process of distilling and cracking mineral oils.

It is an object of this invention to provide a process of distilling and cracking mineral oils to yield a maximum amount of gasolene and a minimum amount of incondensable gases and carbon which is carried on rapidly and in which prolonged high temperatures are avoided.

As well known, natural hydrocarbon oil or crude petroleum is, a mixture of substances of various boiling points. In the ordinary processes of cracking mineral oil, the cracking process is carried on in a combined distilling and cracking zone and the temperature is as high as practicable within the limits of the apparatus in order to insure a high speed of reaction. Such a high temperature, however, is not best for a large portion of the constituents of the hydrocarbon oil. The best results would be obtained if all of the hydrocarbons of a certain boiling point were subjected to a cracking temperature best suited for them.

This theory is in strict accord with the molecular kinetic theory as advanced by Avogadro, which, in brief, is: that molecules are made up of atoms. The atoms are separate entities of matter which vibrate in straight paths, much greater than the diameter of the atoms. When the temperature of the molecule is raised, the rate of vibration increases, as evidenced by the increase of pressure within the system. Now, in the cracking of oils, it is reasonable to suppose that at certain temperatures and pressure, the strain set up in the molecule causes'a rupture to take place in the molecule and as a result two or more molecules are formed. It is also reasonable to suppose that if any particular molecule be subjected to different temperatures, diiferent cleavages will take place. Since in cracking oils higher temperatures give higher percentages of CH H O, H, and C, it is reasonable to suppose that in obtaining the maximum amount of gasolene from a particular mixthe length of the path being ture of hydrocarbon molecules that there is an optimum temperature for every particular molecular decomposition with the formation of a particular class of molecules.

It is an object of the present invention to carry out the cracking process in a two-step operation by providing a distilling zone inwhich the crude petroleum and the like is distilled in a progressive manner, so that the hydrocarbons of a lower boiling point are first distilled off, and, as the temperature is raised, hydrocarbons of higher point are distilled. The vapors thus distilled and consisting of progressively higher boiling points are passed through the cracking zone in which the temperature is maintained, from 100 to 400 C. higher than the boiling point of the vapors passing therethrough, thus adapting the cracking temperature to the particular hydrocarbon vapors passing to the cracking zone.

In the accompanying drawings, which form a part of this specification, I have illustrated an apparatus suitable for carrying out my novel process, and in which the figure shown is a diagrammatic view of the apparatus.

Referring to the drawings, 10 indicates a still, which may be of any preferred construction, heated by a suitable burner 11. 12 indicates a vapor conduit pipe leading to a reaction chamber 13,- which is a vertical pipe preferably having an oval-shaped cross section in order to facilitate the heat trans-- ference from the surrounding furnace 14 to reach the interior of said pipe. 15 is an expansion drum connected to the reaction chamber 13, whence a conduit 16, leading to a dephlegmator 17, is provided with an outlet 18. 19 is a conduit leading from the dephlegmator to a condenser not shown. The heavy hydrocarbons are led from the dephlegmator 17 by means of a pump 20 and by a pipe 21 leading to the still 10.

In the operation of the process, the oil to be treated is distilled in the still 10, the heat being raised gradually toabout 400 C. The vapors of the hydrocarbons of progressively higher boiling points, as the heat is increased in the still, are led to the cracking chamber 13, where they are subjected to a temperature of from 100 to 400 C. higher than the temperature of the entering vapors.

The vapors coming from the still enter the cracking zone at the top thereof and pass downwardly therethrough on to the condensers. During their passage through the cracking zone, the vapors are heated to a temperature of from 100 to 400 C. higher than the temperature of the entering vapors. Since the process is carried on at practically atmospheric pressure, this heating of the vapors will tend to cause them to rise and retard their downward passage, thereby prolonging the reaction time in the cracking zone. rom the cracking zone the vapors are led to the dephlegrnator and condensers, which separate the heavy, the light hydrocarbons, and the incondensable gases in the usual manner. The heavier hydrocarbons are led back into the still to be subjected to the same cycle of operation.

The advantage of my process consists in subjecting a current of hydrocarbon vapors of progressively higher boiling points to a temperature of 100 to 400 C. higher than said boiling point, thereby cracking the hydrocarbons in a rapid and complete manner, avoiding excessively high temperatures, except at the final stages of the cracking process, and producing a maximum amount of gasolene, the yield being in some cases as high as 75% of the crude oil used.

Besides the avoidance of high temperatures, high pressures are avoided as the process is carried on at practically atmospheric pressure.

Furthermore, my process avoids the excessive production of carbon and incondensable hydrocarbons.

While I have found that a difi'erence of 100 to 400 C. in the cracking zone yields the best results, I do not Wish to limit my-J hydrocarbon oils, consisting of distilling thehydrocarbon oils to be treated in a distilling zone, leading the hydrocarbon vapors distilled to a cracking zone, progressively raising the temperature in the distilling zone and maintaining the temperature of the cracking zone at a temperature from 100 to 400 C. higher than the temperature of the entering vapors, and separating the heavier from the lighter hydrocarbons.

2. A process of distilling and cracking hydrocarbon oils, consisting of distilling the hydrocarbon oils to be treated in a distilling zone, leading the hydrocarbon vapors distilled to a cracking zone, progressively raising the temperature in the distilling zone and maintaining the temperature of the cracking zone at a temperature higher than the temperature of the entering vapors, and separating the heavier from the lighter hydrocarbons.

In testimony whereof I have signedmy name to this specification.

J. A. SWATON. 

